var Circle = function(options) {
    this.context = options.context;
    this.color = options.color || '#000000';
    this.radius = options.radius || 10;
    this.position = options.position || new Point(0, 0);
    this.velocity = options.velocity || new Point(0, 0);
    
    this.FULL_CIRCLE = Math.PI * 2;
    
    this.draw = function() {
        
        this.context.fillStyle = this.color;
        this.context.beginPath();
        this.context.arc(
            this.position.x, 
            this.position.y, 
            this.radius, 0, 
            this.FULL_CIRCLE, 
            true
        );
        this.context.closePath();
        this.context.fill();
    };
    
    this.update = function() {
        this.position = this.position.add(this.velocity);
    };
}